The majority of military capability the U.S. promised to send Ukraine, part of a $350 million package, will be delivered within the next week, a senior U.S. defense official told reporters Friday.

In addition to the U.S., 14 countries are also providing military assistance to Ukraine.

The new aid package was expedited so quickly because it has been categorized as “a presidential drawdown,” which bypasses the traditional process of congressional notification, according to the official.

According to another official, this is the largest-ever military support that falls under “a presidential drawdown."

A second official told reporters that weapons were getting into Ukraine through "multiple venues."

Instead of providing new weapons, the U.S. will provide weapons that are in the existing U.S. military arsenal and are eligible to be replaced. The official said the Ukrainians are being provided with weapons they have already received training for in the past.

"I think all of us have been tremendously impressed by how effectively the Ukrainian Armed Forces have been using the equipment that we've provided them," said the official.

Adding, "I think that Kremlin watchers have also been surprised by this, and how they have slowed the Russian advance and performed extremely well on the battlefield."

-ABC News' Luis Martinez

U.S. envoy Linda Thomas-Greenfield addressed the Security Council Friday, warning that, "the world narrowly averted a nuclear catastrophe last night. We all waited to exhale as we watched the horrific situation unfold in real time."

She called Russia's attack on the Zaporizhzhia nuclear power plant "incredibly reckless and dangerous" and said it "threatened the safety of civilians across Russia, Ukraine and Europe."

Thomas-Greenfield urged Russia to withdraw troops from the facility, give operators full access to ensure continued safe operation and assess any damage and to halt any further use of force near Ukraine's nuclear facilities.

She said Russia has killed "thousands of Ukrainians" and "thousands" of Russian soldiers have been killed as well, adding, "President Putin must stop this humanitarian catastrophe by ending this war."

She called on Russia's envoy in the chamber to "say this won't happen again."

International Atomic Energy Agency Director General Rafael Grossi attended the meeting remotely, saying the agency was ready to deploy to Ukraine and establish "basic principles of safety and security starting with the physical integrity" of its nuclear power plants.

Ukraine has requested direct assistance, he said, calling it his agency's "duty" to assist.

The IAEA remains in contact with Ukrainian authorities, including Ukraine's nuclear regulatory agency and the company operating the facility, he said.

-ABC News' Conor Finnegan

Russia's state censor announced Friday it is blocking Facebook in the country.

The state censor, Roskomnadzor, claimed it was taking the step because of alleged freedom of speech violations by Facebook, citing the blocking of several Russian state media channels from the social media platform.

This is part of a broader push by Russian authorities to shut down independent media and social media platforms that might spread dissent against the war in Ukraine.

On Friday, the BBC announced it is temporarily pausing reporting from Russia because of a new law that imposes 15 years in jail for anyone spreading information the authorities claim is “fake” about the war in Ukraine.

-ABC News' Patrick Reevell

Approximately 100,000 children in Ukraine were raised in institutions prior to the war, according to government statistics, a United Nations Children's Fund spokesperson told ABC News.

The spokesperson said many of these institutions are located in hot spots.

These institutions are being evacuated without proper monitoring of the children's situation, according to UNICEF.

The spokesperson said many of the children in institutions like boarding schools and orphanages have disabilities.

- ABC News' Zoe Magee

Ukraine's air force claimed Friday that Russia carried out an alleged false flag airstrike in a Belarusian village near the border with Ukraine.

In a post on Facebook, Ukraine's air force claimed Russian jets took off from a base in Belarus and entered Ukraine's airspace, then a fire started in the village of Kopani.

Ukraine's Defense Minister Oleksy Reznikov earlier claimed in a Facebook post that Russian forces would launch a strike against Kopani to "pull the armed forces of the Republic of Belarus into the war with Ukraine."

-ABC News' Patrick Reevell